How to Sign "Understanding"
To sign "understanding" (or "understand"), start by bringing your dominant hand up to the side of your forehead. Form a closed fist with your palm facing toward your face. Then, quickly flick your index finger straight up so it points toward the ceiling. The motion should look like a sudden idea or a lightbulb turning on in your mind. Adding a slight head nod and an expression of realization helps convey that you truly grasp the concept.